Department of Restorative Dentistry, Faculty of Dentistry, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
J Endod. 2011 Jul;37(7):1002-7. doi: 10.1016/j.joen.2011.03.017. Epub 2011 May 12.
The aim of this study was to evaluate the root canal preparation in flat-oval canals treated with either rotary or self-adjusting file (SAF) by using micro-tomography analysis.
Forty mandibular incisors were scanned before and after root canal instrumentation with rotary instruments (n = 20) or SAF (n = 20). Changes in canal volume, surface area, and cross-sectional geometry were compared with preoperative values. Data were compared by independent sample t test and χ(2) test between groups and paired sample t test within the group (α = 0.05).
Overall, area, perimeter, roundness, and major and minor diameters revealed no statistical difference between groups (P > .05). In the coronal third, percentage of prepared root canal walls and mean increases of volume and area were significantly higher with SAF (92.0%, 1.44 ± 0.49 mm(3), 0.40 ± 0.14 mm(2), respectively) than rotary instrumentation (62.0%, 0.81 ± 0.45 mm(3), 0.23 ± 0.15 mm(2), respectively) (P < .05). SAF removed dentin layer from all around the canal, whereas rotary instrumentation showed substantial untouched areas.
In the coronal third, mean increases of area and volume of the canal as well as the percentage of prepared walls were significantly higher with SAF than with rotary instrumentation. By using SAF instruments, flat-oval canals were homogenously and circumferentially prepared. The size of the SAF preparation in the apical third of the canal was equivalent to those prepared with #40 rotary file with a 0.02 taper.
本研究旨在通过微断层扫描分析评估使用旋转器械或自调整锉（SAF）对扁平-卵圆形根管进行根管预备的效果。
40 颗下颌切牙在使用旋转器械（n = 20）或 SAF（n = 20）根管预备前后进行扫描。比较术前和术后根管容积、表面积和横截面几何形状的变化。采用独立样本 t 检验和组间 χ(2)检验以及组内配对样本 t 检验对数据进行比较（α = 0.05）。
总体而言，各组间面积、周长、圆度以及主、副根管直径均无统计学差异（P >.05）。在根管冠 1/3 区域，SAF（92.0%，1.44 ± 0.49 mm(3)，0.40 ± 0.14 mm(2)）预备后根管壁的百分比和容积及表面积的平均增加量显著高于旋转器械（62.0%，0.81 ± 0.45 mm(3)，0.23 ± 0.15 mm(2)）（P <.05）。SAF 从根管周围去除了牙本质层，而旋转器械则显示出大量未触及的区域。
在根管冠 1/3 区域，SAF 预备后根管的表面积和容积的平均增加量以及根管壁的预备百分比显著高于旋转器械。使用 SAF 器械可使扁平-卵圆形根管得到均匀、全面的预备。SAF 在根管根尖 1/3 区域的预备尺寸与 0.02 锥度的 #40 号旋转锉相当。
